Diagnosis of collagen IX destruction

A method for detecting or monitoring the presence of protein fragments, cleaved at novel cleaving sites near the N-terminal part of the collagen IX alpha 1 chain, close to the C-terminal part of the NC4 domain, and at the COL3 domain close to the NC3 domain. Neoepitope antibodies against the neoepitopes were created by the cleavages and an epitope in the cleaved N-terminal part of the NC4 domain unique to collagen IX. A diagnostic kit and antibodies useful in carrying out such methods are also presented.